CA1291864C - Electrical contact assembly with composite contact construction - Google Patents
Electrical contact assembly with composite contact constructionInfo
- Publication number
- CA1291864C CA1291864C CA000547702A CA547702A CA1291864C CA 1291864 C CA1291864 C CA 1291864C CA 000547702 A CA000547702 A CA 000547702A CA 547702 A CA547702 A CA 547702A CA 1291864 C CA1291864 C CA 1291864C
- Authority
- CA
- Canada
- Prior art keywords
- metallic material
- contact
- silver
- wire
- slug
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
- H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49117—Conductor or circuit manufacturing
- Y10T29/49204—Contact or terminal manufacturing
- Y10T29/49208—Contact or terminal manufacturing by assembling plural parts
- Y10T29/4921—Contact or terminal manufacturing by assembling plural parts with bonding
- Y10T29/49211—Contact or terminal manufacturing by assembling plural parts with bonding of fused material
- Y10T29/49213—Metal
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Manufacture Of Switches (AREA)
- Contacts (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method of producing a nonwelding contact assembly for an electrical switch using a composite contact material formed by extruding a metal oxide core surrounded by a metal or metal alloy sheath with good welding properties to form a wire of core material having a layer of the metal or metal alloy metallurgically bonded thereto. A segment of the wire is resistance welded to a contact carrier and coined to the desired contact shape, after which the layer on the contact surface is sufficiently thin that it is oxidized to provide nonwelding characteristics after a few switch operations.
A method of producing a nonwelding contact assembly for an electrical switch using a composite contact material formed by extruding a metal oxide core surrounded by a metal or metal alloy sheath with good welding properties to form a wire of core material having a layer of the metal or metal alloy metallurgically bonded thereto. A segment of the wire is resistance welded to a contact carrier and coined to the desired contact shape, after which the layer on the contact surface is sufficiently thin that it is oxidized to provide nonwelding characteristics after a few switch operations.
Description
lZ'~18~i~
~9B~E~ TION
The present inventl~n rel~te~ generally to 5 ~lectrlc~l contact materlals and a~se~blies, and more p~rticulnrly to a method of producing ~ ~elded contact Assembly havlng a nonweldlng electrlcal contact surface and to a compo~lte materlal for produclng such contact as~embly.
0 It 18 nece~ary and ~ell known ln connectlon wlth electric~l switches for hlgh current ~nd hlgh voltage appllcation~ to use a contact materlal whlch res$st~ welding to prevent fuslng of electrlcal contacts due to arclng upon breaking and/or making of the cont~ct~. ~owever, the same prop*rtle~ whlch make a m~ter~l suitable for nonwelding contact~ also llmit tbe ~s~embly and fabrlcation processes ~hlch can be used. Wlth such materlals, heat b~sed bondlnq methods 6 ~a ~'2~
such a~ solder~ng, bralslng or weldlng are dlfflcult 20 to use, and ~dhesion of tbe contact to the contact carrier ~ay not be structurally sound. Further, the electrlcal propertles of such an assembly may be adversely affected. Yet further, co~tact ~aterl~ls ~ade o~ ~ilver and ~etal oxlde compo~ltes, which have 1~9113f~4 hlghly deslrable nonweldlng propertl~s, cannot be practlcally welded by re~i~t~nce weldlng methods.
Thls is a dlstlnct dlsadvantage because reslstance welding is one of the moat ineYpensive, slmple and reli~ble methods of attaching a contact to a contact carrler.
A variety of technlques have been attempted to permit the use of welding in attaching contacts having nonwelding characteristics to contact carrlers. One approach has been to form a layer of a metal oxide on a base material having good welding properties. The base materlal can then be welded to the contact carrier and the oxide layer on the base material forms the electrical contact surface.
Another approach has been to form or bond a layer of material having good welding characteristic~ on a nonweldlng material which provides the electrical contact curface. For example, U.S. patent 2,425,053 issued to M. Swinehart on August 5, 1947 and ~.S.
patent 2,468,888 1~6ued to H. Mekelburg on May 3, 1949 each di~close electrical contact~ which are individually formed by placing a layer of ~ilver or sllver alloy powder in a sultable die cavity, that layer then being covered with a layer of a ~uitable metal oYide powder. Thereafter the powder in the cavity i8 subjected to a high pre~sure molding operation and heat ~intering. The resulting contact has ~ nonweldlng metal oxlde elec~rical contact ~urface and a metal backing which exhibits good weldlng properties~ A d~advantage is that this process, in which the contacts are indiYldually ormed, i8 relatively 810w and expensive.
Another technique i~ shown in ~.S. patent 4,342,893 issued to H. Wolf on August 3, 1982. In this technique, a-ribbon of composite contac~ material i~ formed by a rolling proces~ in which a wire of a metal oxide i8 rolled together with one or more wires of a metal such as a silver copper alloy solder to form a tape material having a nonwelding electrical contact ~urface and one or more beads of a material with good welding properties on the opposite surface for permitting welding of segment~ of the tape to a contact carrier. One of the disadvantage~ of a rolling operat~ng i8 that it cannot be conducted at the temperature ~ufficlently high to achieve a metallurgical bond between the metal alloy and metal oxide materiala. For pre~ent purposes, a metallurgical bond is defined to be a bond in which there i8 ~ignificant diffusion of the two materials into one another at their interface. A metallurgical bond between the ~etal and metal oxide materials i8 2s desirable and/or necessary in order to achieve required structural properties of the compo~ite 1~318ti'~
contact mate~1~1 and of the contact/contact carrler a~ embly. In the technlque de~cribed ln the previou~ly identified Wolf patent, lf a ~ufficlently high temperature for achieving a metallurgical bond 1B
S used, the metal and/or metal oxide materialR would tend to adhere to the forming rollers.
The applicant ha~ avoided the foregoing problems by providing a hot extruded compo~ite contact material and method of producing electrical switch contact assemblies in whlch a true metallurgical bond is formed between the nonwelding metal oxide material and a metal layer having good welding characteri~tics. The composite contact material 15 economically producible in wire form and suitable for u~e in highly integrated automatic switch a~sembly processes and machine~.
Su~ARY OF $~E INVENTIQ~
~ he invention i8 a method of producing a composite electrical contact material and a welded contact assembly using such material, the contact assembly having nonwelding characteristics at its electrical contact ~urface. The composite material i8 produced by forming a cylindrical core of a firct metallic material having nonwelding characteristic~
and a tubular sleeve o~ a second metallic material having good weldlng properties. The core is positioned w~thin the sleeve to folm a ~lug which is 12S~ 4 extruded under high temperature into a wire having a core of the first material with an outer layer of the second material metallurgically bonded thereto. The contact assembly is pro-duced by forming a contact carrier, welding a segment of the wire containing sufficient material to form a desired contact onto the contact carrier, and coining the segment to the de-sired contact shape.
In accordance with the present invention there is provided a method of producing a nonwelding contact assembly for an electrical switch, comprising the steps of:
forming a cylindrical billet of a first nonwelding metallic material:
forming a tubular section of a second metallic material having good welding properties configured to fit over said cylindrical billet;
inserting said cylindrical billet into said tubular section to form a slug having a core of the first material and a sheath of the second material;
extruding said slug at an elevated temperature to form a wire having an outer layer of the second material metal-lurgically bonded to a core of the first material;
forming a switch contact carrier;
welding a segment of said wire containing sufficient material to form a desired contact configuration to said contact carrier; and coining the segment of wire welded to the contact carrier to form a contact having an electrical contact surface thereon.
In accordance with the present invention there is provided a method of producing a welded electrical contact assembly having a contact with nonwelding characteristics at its electrical contact surface, comprising the steps of:
~, 1i~91~
-5a-producing a slug having a core of a first metallic mat-erial exhibiting nonwelding characteristics and having a sheath of a second metallic material exhibiting good welding charac-teristics extruding the slug to form a wire of the first metallic material having a layer of the second metallic material bonded thereto, the extrusion process and dimensions of the core and sheath being selected to produce a metallurgical bond between the first and second materials;
forming an electric contact carrier of a metal exhibiting good welding characteristics;
welding a segment of said wire containing sufficient material to form a desired contact configuration to the contact carrier; and coining the segment of wire welded to the contact carrier to form an electrical contact.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic illustration, partially in section, of a portion of extrusion apparatus with a slug of composite material in the chamber thereof prior to initiation of the extrusion process;
Figure 2 is a view of the apparatus of Figure 1 during the extrusion process and showing the slug being formed into a wire;
Figure 3 is a cross-sectional view of the wire shown in Figure 2;
Figure 4 is a partial perspective view of a contact carrier having a segment of the wire of Figures 2 and 3 welded thereon; and Figure 5 is a view of the contact carrier of Figure 4 after the segment of wire thereon has been coined into a de-sired contact shape.
~91~364 $n Flgures 1 and 2, reference numeral 10 generally ldentifles an e~truslon press having ~ dle 11 with a cylindrlcal cavi~y 12 therein terminating in a nozzel 13. A ram 14 18 adapted to be drlven by means not shown to allde wlthin cavity 12 and e~trude material thereln through nozzel 13.
Located withln chamber 12 i8 a composite slug of electrically conductive materials comprising a lo cylindrical core or billet 20 of a metal oxide such as silver cadimum oside or æliver tin oYide having nonwelding propertie~. Surrounding core 20 iB a sheath or fileeve of a metal alloy having good welding propertieR, such aa flne silver, silver cadimum or ~ilver tin. Sleeve 21 may have been formed by ca~ting a tubular section of the de~ired metal, and machining it as neces~ary to provide an appropriate inner diameter for accommodating billet 20 and a wall th~ckne~s which, after e~truslon and other processing, will provlde a layer of the appropriate thickness on the core material of billet 20.
The eYtru~ion process is carrled out at a temperature which iB sufficlently high to produce a desired degree of plastlcity of the materlals of core billet 20 and sleeve 21. As ahown in Figures 2 and 3, the re~ult iB a wire 22 having a core 23 of the metal 1~911~
_,_ oxlde of blllet 20 surrounded by an outer layer 2~ of the mot~l of ~leeve 21. ~he pre~sure ~nd temperature utillzed ln the e~tru~lon proces~ cau e n metallurglcal bond at the lnterface 2S between core 23 and outer l~yer 2~. Accordingly, the bond provldes e~cellent ~dhesion between the materlala.
After extrusion, wire 22 i8 cold drawn and anne~led one or more times to achieve desired wire dimen~lon~ and temper. Because of the hardnees and lo brittleness of the oxide ~aterial~ under con~ideratlon, the maximum reduction which can be achleved wlth acceptable result~ durtng a cold drawing operation is appro~imately 20~. It iz, however, pointed out that having the core material confined within a layer of more ductile material provide~ more latitude in working the core material during both the eYtrusion and cold draw$ng processes.
Figures 4 and 5 illustrate how fiegments of wire 22 ~ay be used to form an electrical contact in a ~witch contact as~embly. Reference numeral 30 identif$es ~ contact carrier typically stamped from a copper or copper alloy sheet or strip. Reference nu~eral 31 identifie~ a wire segment sheared from wire prepared a~ prevlou~ly described. Since the outer layer of wire 31 i~ of ~ materlal whicb has good welding properties, it can be easily and ~ecurely 12'~b~}
welded to carrier 30 by conventional resistance welding techni-ques. Following welding of wire segment 31 to carrier 30, the wire segment is coined into a desired contact shape 32 as shown in Figure 5. The coining opecation leaves a thin layer o-f the metal or metal alloy of sleeve 21 on electrical contact surface 33. Although such material has good welding properties and would not normally be suitable for the electrical contact sur-faces of a high voltage or high current switch, it has been found that if this layer is kept in the order of .002 to .004 inches and preferably in the order of .003 inches, it oxidizes during the course of a few switch operations to form a material having properties similar to the nonwelding properties of the underlying metal oxide.
Fabrication of the contact assembly has been described as several discrete steps. However, on a modern high speed integrated manufacturing machine, shearing of a wire segment 31, resistance welding it to a contact carrier and coining it into a desired contact shape occurs almost simulta-neously at a single station. Wire for forming segments 31 and a strip of contact carriers 30 may be continuously fed to the station, thereby resulting in a very high production rate.
Thus, it can be seen that the composite contact material devised by the applicant is well suited to modern high speed production processes. Furthermore, ~, 1~1864 _g the composlte cont~ct materlal 18 rel~t~vely lne~pen~lve to produce, i~ readlly ~ttached to ~
contact carrler by conventional reslstance weldlng technlque~, and results ln A high cap~city electrlcal swltch with e~cellent resi~tance to contact fu~ion.
Although the applicant's method h~ been described ln a particular ~orm for lllustrative purposes, variou modlflcations to the disclo~ed method which do not depart from the appllcant's lo contemplatlon and teaching will be apparent to those of ordlnary skill in the relevant ~rts. It iB
intended that coverage not be llmlted by the partlcular details disclosed, but only by the terms of the following clalms.
~9B~E~ TION
The present inventl~n rel~te~ generally to 5 ~lectrlc~l contact materlals and a~se~blies, and more p~rticulnrly to a method of producing ~ ~elded contact Assembly havlng a nonweldlng electrlcal contact surface and to a compo~lte materlal for produclng such contact as~embly.
0 It 18 nece~ary and ~ell known ln connectlon wlth electric~l switches for hlgh current ~nd hlgh voltage appllcation~ to use a contact materlal whlch res$st~ welding to prevent fuslng of electrlcal contacts due to arclng upon breaking and/or making of the cont~ct~. ~owever, the same prop*rtle~ whlch make a m~ter~l suitable for nonwelding contact~ also llmit tbe ~s~embly and fabrlcation processes ~hlch can be used. Wlth such materlals, heat b~sed bondlnq methods 6 ~a ~'2~
such a~ solder~ng, bralslng or weldlng are dlfflcult 20 to use, and ~dhesion of tbe contact to the contact carrier ~ay not be structurally sound. Further, the electrlcal propertles of such an assembly may be adversely affected. Yet further, co~tact ~aterl~ls ~ade o~ ~ilver and ~etal oxlde compo~ltes, which have 1~9113f~4 hlghly deslrable nonweldlng propertl~s, cannot be practlcally welded by re~i~t~nce weldlng methods.
Thls is a dlstlnct dlsadvantage because reslstance welding is one of the moat ineYpensive, slmple and reli~ble methods of attaching a contact to a contact carrler.
A variety of technlques have been attempted to permit the use of welding in attaching contacts having nonwelding characteristics to contact carrlers. One approach has been to form a layer of a metal oxide on a base material having good welding properties. The base materlal can then be welded to the contact carrier and the oxide layer on the base material forms the electrical contact surface.
Another approach has been to form or bond a layer of material having good welding characteristic~ on a nonweldlng material which provides the electrical contact curface. For example, U.S. patent 2,425,053 issued to M. Swinehart on August 5, 1947 and ~.S.
patent 2,468,888 1~6ued to H. Mekelburg on May 3, 1949 each di~close electrical contact~ which are individually formed by placing a layer of ~ilver or sllver alloy powder in a sultable die cavity, that layer then being covered with a layer of a ~uitable metal oYide powder. Thereafter the powder in the cavity i8 subjected to a high pre~sure molding operation and heat ~intering. The resulting contact has ~ nonweldlng metal oxlde elec~rical contact ~urface and a metal backing which exhibits good weldlng properties~ A d~advantage is that this process, in which the contacts are indiYldually ormed, i8 relatively 810w and expensive.
Another technique i~ shown in ~.S. patent 4,342,893 issued to H. Wolf on August 3, 1982. In this technique, a-ribbon of composite contac~ material i~ formed by a rolling proces~ in which a wire of a metal oxide i8 rolled together with one or more wires of a metal such as a silver copper alloy solder to form a tape material having a nonwelding electrical contact ~urface and one or more beads of a material with good welding properties on the opposite surface for permitting welding of segment~ of the tape to a contact carrier. One of the disadvantage~ of a rolling operat~ng i8 that it cannot be conducted at the temperature ~ufficlently high to achieve a metallurgical bond between the metal alloy and metal oxide materiala. For pre~ent purposes, a metallurgical bond is defined to be a bond in which there i8 ~ignificant diffusion of the two materials into one another at their interface. A metallurgical bond between the ~etal and metal oxide materials i8 2s desirable and/or necessary in order to achieve required structural properties of the compo~ite 1~318ti'~
contact mate~1~1 and of the contact/contact carrler a~ embly. In the technlque de~cribed ln the previou~ly identified Wolf patent, lf a ~ufficlently high temperature for achieving a metallurgical bond 1B
S used, the metal and/or metal oxide materialR would tend to adhere to the forming rollers.
The applicant ha~ avoided the foregoing problems by providing a hot extruded compo~ite contact material and method of producing electrical switch contact assemblies in whlch a true metallurgical bond is formed between the nonwelding metal oxide material and a metal layer having good welding characteri~tics. The composite contact material 15 economically producible in wire form and suitable for u~e in highly integrated automatic switch a~sembly processes and machine~.
Su~ARY OF $~E INVENTIQ~
~ he invention i8 a method of producing a composite electrical contact material and a welded contact assembly using such material, the contact assembly having nonwelding characteristics at its electrical contact ~urface. The composite material i8 produced by forming a cylindrical core of a firct metallic material having nonwelding characteristic~
and a tubular sleeve o~ a second metallic material having good weldlng properties. The core is positioned w~thin the sleeve to folm a ~lug which is 12S~ 4 extruded under high temperature into a wire having a core of the first material with an outer layer of the second material metallurgically bonded thereto. The contact assembly is pro-duced by forming a contact carrier, welding a segment of the wire containing sufficient material to form a desired contact onto the contact carrier, and coining the segment to the de-sired contact shape.
In accordance with the present invention there is provided a method of producing a nonwelding contact assembly for an electrical switch, comprising the steps of:
forming a cylindrical billet of a first nonwelding metallic material:
forming a tubular section of a second metallic material having good welding properties configured to fit over said cylindrical billet;
inserting said cylindrical billet into said tubular section to form a slug having a core of the first material and a sheath of the second material;
extruding said slug at an elevated temperature to form a wire having an outer layer of the second material metal-lurgically bonded to a core of the first material;
forming a switch contact carrier;
welding a segment of said wire containing sufficient material to form a desired contact configuration to said contact carrier; and coining the segment of wire welded to the contact carrier to form a contact having an electrical contact surface thereon.
In accordance with the present invention there is provided a method of producing a welded electrical contact assembly having a contact with nonwelding characteristics at its electrical contact surface, comprising the steps of:
~, 1i~91~
-5a-producing a slug having a core of a first metallic mat-erial exhibiting nonwelding characteristics and having a sheath of a second metallic material exhibiting good welding charac-teristics extruding the slug to form a wire of the first metallic material having a layer of the second metallic material bonded thereto, the extrusion process and dimensions of the core and sheath being selected to produce a metallurgical bond between the first and second materials;
forming an electric contact carrier of a metal exhibiting good welding characteristics;
welding a segment of said wire containing sufficient material to form a desired contact configuration to the contact carrier; and coining the segment of wire welded to the contact carrier to form an electrical contact.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic illustration, partially in section, of a portion of extrusion apparatus with a slug of composite material in the chamber thereof prior to initiation of the extrusion process;
Figure 2 is a view of the apparatus of Figure 1 during the extrusion process and showing the slug being formed into a wire;
Figure 3 is a cross-sectional view of the wire shown in Figure 2;
Figure 4 is a partial perspective view of a contact carrier having a segment of the wire of Figures 2 and 3 welded thereon; and Figure 5 is a view of the contact carrier of Figure 4 after the segment of wire thereon has been coined into a de-sired contact shape.
~91~364 $n Flgures 1 and 2, reference numeral 10 generally ldentifles an e~truslon press having ~ dle 11 with a cylindrlcal cavi~y 12 therein terminating in a nozzel 13. A ram 14 18 adapted to be drlven by means not shown to allde wlthin cavity 12 and e~trude material thereln through nozzel 13.
Located withln chamber 12 i8 a composite slug of electrically conductive materials comprising a lo cylindrical core or billet 20 of a metal oxide such as silver cadimum oside or æliver tin oYide having nonwelding propertie~. Surrounding core 20 iB a sheath or fileeve of a metal alloy having good welding propertieR, such aa flne silver, silver cadimum or ~ilver tin. Sleeve 21 may have been formed by ca~ting a tubular section of the de~ired metal, and machining it as neces~ary to provide an appropriate inner diameter for accommodating billet 20 and a wall th~ckne~s which, after e~truslon and other processing, will provlde a layer of the appropriate thickness on the core material of billet 20.
The eYtru~ion process is carrled out at a temperature which iB sufficlently high to produce a desired degree of plastlcity of the materlals of core billet 20 and sleeve 21. As ahown in Figures 2 and 3, the re~ult iB a wire 22 having a core 23 of the metal 1~911~
_,_ oxlde of blllet 20 surrounded by an outer layer 2~ of the mot~l of ~leeve 21. ~he pre~sure ~nd temperature utillzed ln the e~tru~lon proces~ cau e n metallurglcal bond at the lnterface 2S between core 23 and outer l~yer 2~. Accordingly, the bond provldes e~cellent ~dhesion between the materlala.
After extrusion, wire 22 i8 cold drawn and anne~led one or more times to achieve desired wire dimen~lon~ and temper. Because of the hardnees and lo brittleness of the oxide ~aterial~ under con~ideratlon, the maximum reduction which can be achleved wlth acceptable result~ durtng a cold drawing operation is appro~imately 20~. It iz, however, pointed out that having the core material confined within a layer of more ductile material provide~ more latitude in working the core material during both the eYtrusion and cold draw$ng processes.
Figures 4 and 5 illustrate how fiegments of wire 22 ~ay be used to form an electrical contact in a ~witch contact as~embly. Reference numeral 30 identif$es ~ contact carrier typically stamped from a copper or copper alloy sheet or strip. Reference nu~eral 31 identifie~ a wire segment sheared from wire prepared a~ prevlou~ly described. Since the outer layer of wire 31 i~ of ~ materlal whicb has good welding properties, it can be easily and ~ecurely 12'~b~}
welded to carrier 30 by conventional resistance welding techni-ques. Following welding of wire segment 31 to carrier 30, the wire segment is coined into a desired contact shape 32 as shown in Figure 5. The coining opecation leaves a thin layer o-f the metal or metal alloy of sleeve 21 on electrical contact surface 33. Although such material has good welding properties and would not normally be suitable for the electrical contact sur-faces of a high voltage or high current switch, it has been found that if this layer is kept in the order of .002 to .004 inches and preferably in the order of .003 inches, it oxidizes during the course of a few switch operations to form a material having properties similar to the nonwelding properties of the underlying metal oxide.
Fabrication of the contact assembly has been described as several discrete steps. However, on a modern high speed integrated manufacturing machine, shearing of a wire segment 31, resistance welding it to a contact carrier and coining it into a desired contact shape occurs almost simulta-neously at a single station. Wire for forming segments 31 and a strip of contact carriers 30 may be continuously fed to the station, thereby resulting in a very high production rate.
Thus, it can be seen that the composite contact material devised by the applicant is well suited to modern high speed production processes. Furthermore, ~, 1~1864 _g the composlte cont~ct materlal 18 rel~t~vely lne~pen~lve to produce, i~ readlly ~ttached to ~
contact carrler by conventional reslstance weldlng technlque~, and results ln A high cap~city electrlcal swltch with e~cellent resi~tance to contact fu~ion.
Although the applicant's method h~ been described ln a particular ~orm for lllustrative purposes, variou modlflcations to the disclo~ed method which do not depart from the appllcant's lo contemplatlon and teaching will be apparent to those of ordlnary skill in the relevant ~rts. It iB
intended that coverage not be llmlted by the partlcular details disclosed, but only by the terms of the following clalms.
Claims (17)
1. A method of producing a nonwelding contact assembly for an electrical switch comprising the steps of:
forming a cylindrical billet of a first non-welding metallic material;
forming a tubular section of a second metallic material having good welding properties configured to fit over said cylindrical billets inserting said cylindrical billet into said tubular section to form a slug having a core of the first material and a sheath of the second material;
extruding said slug at an elevated temperature to form a wire having an outer layer of the second material metallurgically bonded to a core of the first materials forming a switch contact carrier;
welding a segment of said wire containing sufficient material to form a desired contact configuration to said contact carrier; and coining the segment of wire welded to the contact carrier to form a contact having an electrical contact surface thereon.
forming a cylindrical billet of a first non-welding metallic material;
forming a tubular section of a second metallic material having good welding properties configured to fit over said cylindrical billets inserting said cylindrical billet into said tubular section to form a slug having a core of the first material and a sheath of the second material;
extruding said slug at an elevated temperature to form a wire having an outer layer of the second material metallurgically bonded to a core of the first materials forming a switch contact carrier;
welding a segment of said wire containing sufficient material to form a desired contact configuration to said contact carrier; and coining the segment of wire welded to the contact carrier to form a contact having an electrical contact surface thereon.
2. The method of claim 1 wherein said tubular section is formed by casting a tube of the second metallic material.
3. The method of claim 2 wherein the step of extruding said slug at an elevated temperature to form a wire is followed by the steps of cold drawing and annealing the wire to achieve a desired final dimension and temper.
4. The method of claim 3 wherein the dimensions of said billet and said tubular section and the variables of said coining process are selected to produce a layer of the second metallic material having a thickness in the range of .002 to .004 inches on the electrical contact surface of said contact.
5. The method of claim 4 wherein the first metallic material is silver cadimum oxide.
6. The method of claim 5 wherein the second metallic material is a silver cadimum alloy.
7. The method of claim 5 wherein the second metallic material is fine silver.
8. The method of claim 4 wherein the first metallic material is silver tin oxide.
9. The method of claim 8 wherein the second metallic material is a silver tin alloy.
10. The method of claim 8 wherein the second metallic material is fine silver.
11. A method of producing a welded electrical contact assembly having a contact with nonwelding characteristics at its electrical contact surface, comprising the steps of:
producing a slug having a core of a first metallic material exhibiting nonwelding chracteristics and having a sheath of a second metallic material exhibiting good welding characteristics;
extruding the slug to form a wire of the first metallic material having a layer of the second metallic material bonded thereto, the extrusion process and dimensions of the core and sheath being selected to produce a metallurgical bond between the first and second materials;
forming an electric contact carrier of a metal exhibiting good welding characteristics;
welding a segment of said wire containing sufficient material to form a desired contact configuration to the contact carrier; and coining the segment of wire welded to the contact carrier to form an electrical contact.
producing a slug having a core of a first metallic material exhibiting nonwelding chracteristics and having a sheath of a second metallic material exhibiting good welding characteristics;
extruding the slug to form a wire of the first metallic material having a layer of the second metallic material bonded thereto, the extrusion process and dimensions of the core and sheath being selected to produce a metallurgical bond between the first and second materials;
forming an electric contact carrier of a metal exhibiting good welding characteristics;
welding a segment of said wire containing sufficient material to form a desired contact configuration to the contact carrier; and coining the segment of wire welded to the contact carrier to form an electrical contact.
12. The method of claim 11 wherein the step of extruding the slug is performed at an elevated temperature.
13. The method of claim 12 wherein the sheath of a second metallic material is formed by casting and the desired final dimensions for the sheath are achieved by machining.
14. The method of claim 13 wherein the first metallic material is silver cadimum oxide and the second metallic material is a silver cadimum alloy.
15. The method of claim 13 wherein the first metallic material is silver cadimum oxide and the second metallic material is fine silver.
16. The method of claim 13 wherein the first metallic material is silver tin oxide and the second metallic material is a silver tin alloy.
17. The method of claim 13 wherein the first material is silver tin oxide and the second metallic material is fine silver.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US923,799 | 1986-10-27 | ||
| US06/923,799 US4706383A (en) | 1986-10-27 | 1986-10-27 | Electrical contact assembly with composite contact construction |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1291864C true CA1291864C (en) | 1991-11-12 |
Family
ID=25449283
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000547702A Expired - Fee Related CA1291864C (en) | 1986-10-27 | 1987-09-24 | Electrical contact assembly with composite contact construction |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4706383A (en) |
| EP (1) | EP0265878B1 (en) |
| JP (1) | JPH0736298B2 (en) |
| CA (1) | CA1291864C (en) |
| DE (1) | DE3785140T2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4142374A1 (en) * | 1991-12-20 | 1993-06-24 | Siemens Ag | METHOD FOR PRELIMINATING CONTACT PIECES FOR ELECTRICAL SWITCHING DEVICES |
| US5416969A (en) * | 1992-05-11 | 1995-05-23 | Alps Electric Co., Ltd. | Sliding contact producing method |
| US5497133A (en) * | 1995-04-12 | 1996-03-05 | Honeywell Inc. | Switch with improved contacts for use in high temperature environments |
| US6173495B1 (en) * | 1999-05-12 | 2001-01-16 | Trw Inc. | High strength low carbon air bag quality seamless tubing |
| DE102010014745B4 (en) * | 2010-01-15 | 2011-09-22 | Tyco Electronics Amp Gmbh | Electric contact element and method for producing an electrical contact element |
| CN105397424A (en) * | 2015-12-10 | 2016-03-16 | 宋和明 | Machining method for constant-arc contact special-shaped bank |
| PL239816B1 (en) * | 2020-02-28 | 2022-01-10 | Politechnika Poznanska | Method of producing a fuse cover |
| PL239817B1 (en) * | 2020-02-28 | 2022-01-10 | Politechnika Poznanska | Press stamp for multi-operative shaping of the fuse cover |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2434992A (en) * | 1943-09-27 | 1948-01-27 | Metals & Controls Corp | Electrical contact |
| US2425053A (en) * | 1944-06-23 | 1947-08-05 | Cutler Hammer Inc | Silver-backed nonwelding contact and method of making the same |
| US2468888A (en) * | 1944-09-25 | 1949-05-03 | Cutler Hammer Inc | Metal-backed nonwelding contact |
| GB653796A (en) * | 1946-07-01 | 1951-05-23 | Igranic Electric Co Ltd | Electrical contacts and contact materials and methods of making same |
| GB910859A (en) * | 1959-12-01 | 1962-11-21 | Gibson Electric Company | Method of making composite electrical contact bodies |
| US3258830A (en) * | 1964-02-28 | 1966-07-05 | Albert F Pityo | Method of producing an electrical contact assembly |
| GB1048520A (en) * | 1964-12-23 | 1966-11-16 | Talon Inc | Manufacture of a composite electrical contact rivet assembly |
| US3628235A (en) * | 1969-06-25 | 1971-12-21 | Texas Instruments Inc | Method of making edgelay material |
| DE7733326U1 (en) * | 1977-10-28 | 1980-04-24 | Bihler, Otto, 8959 Trauchgau | Device for producing electrical contact parts |
| JPS5546213A (en) * | 1978-09-26 | 1980-03-31 | Taira Denki Kk | Disk type composite electric contact |
| DE2844888C2 (en) * | 1978-10-14 | 1983-02-24 | W.C. Heraeus Gmbh, 6450 Hanau | Raw material for the production of electrical contacts |
| JPS59217912A (en) * | 1983-05-25 | 1984-12-08 | 株式会社戸上電機製作所 | Method of producing electric contact and electric contact material used for same method |
-
1986
- 1986-10-27 US US06/923,799 patent/US4706383A/en not_active Expired - Lifetime
-
1987
- 1987-09-24 CA CA000547702A patent/CA1291864C/en not_active Expired - Fee Related
- 1987-10-24 EP EP87115630A patent/EP0265878B1/en not_active Expired - Lifetime
- 1987-10-24 DE DE8787115630T patent/DE3785140T2/en not_active Expired - Fee Related
- 1987-10-27 JP JP62271608A patent/JPH0736298B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE3785140T2 (en) | 1993-08-05 |
| EP0265878B1 (en) | 1993-03-31 |
| DE3785140D1 (en) | 1993-05-06 |
| EP0265878A3 (en) | 1989-11-08 |
| JPH0736298B2 (en) | 1995-04-19 |
| US4706383A (en) | 1987-11-17 |
| JPS63124314A (en) | 1988-05-27 |
| EP0265878A2 (en) | 1988-05-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |